In 2015, the writer Ottessa Moshfegh published her debut novel, Eileen. Set in 1964, the book takes its title from the main character, a 24-year-old prison secretary who lives with her alcoholic ex-cop father. Eileen becomes obsessed with Rebecca, her older co-worker. The friendship results in death.

The novel is the first of Moshfegh’s books to be adapted for the screen—though Margot Robbie is currently developing her 2018 best-seller, My Year of Rest and Relaxation, into a feature. Moshfegh, who is also the author of the novels Death in Her Hands and Lapvona, collaborated with her husband, Luke Goebel, on the script. Directed by William Oldroyd, the movie stars Thomasin McKenzie as Eileen and Anne Hathaway as Rebecca. The film earned raves at the Sundance Film Festival this week, where it premiered. Ahead of a year on the film festival circuit, she answers our questionnaire about what she packs, eats, and buys while traveling.